feat(01-03): add test infrastructure, protocol version interceptor, and app bootstrap

- AbstractClickHouseIT base class with Testcontainers ClickHouse and schema init
- ProtocolVersionInterceptor validates X-Cameleer-Protocol-Version:1 on data/agent paths
- WebConfig registers interceptor with path patterns, excludes health/docs
- Cameleer3ServerApplication with @EnableScheduling and component scanning
- application-test.yml with small buffer config for tests

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

cameleer3-server-app/src/main/java/com/cameleer3/server/app/Cameleer3ServerApplication.java

@@ -0,0 +1,25 @@
+package com.cameleer3.server.app;
+
+import com.cameleer3.server.app.config.IngestionConfig;
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.boot.context.properties.EnableConfigurationProperties;
+import org.springframework.scheduling.annotation.EnableScheduling;
+
+/**
+ * Main entry point for the Cameleer3 Server application.
+ * <p>
+ * Scans {@code com.cameleer3.server.app} and {@code com.cameleer3.server.core} packages.
+ */
+@SpringBootApplication(scanBasePackages = {
+        "com.cameleer3.server.app",
+        "com.cameleer3.server.core"
+})
+@EnableScheduling
+@EnableConfigurationProperties(IngestionConfig.class)
+public class Cameleer3ServerApplication {
+
+    public static void main(String[] args) {
+        SpringApplication.run(Cameleer3ServerApplication.class, args);
+    }
+}

cameleer3-server-app/src/main/java/com/cameleer3/server/app/config/WebConfig.java

@@ -0,0 +1,34 @@
+package com.cameleer3.server.app.config;
+
+import com.cameleer3.server.app.interceptor.ProtocolVersionInterceptor;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
+import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
+
+/**
+ * Web MVC configuration.
+ * <p>
+ * Registers the {@link ProtocolVersionInterceptor} on data and agent endpoint paths,
+ * excluding health, API docs, and Swagger UI paths that do not require protocol versioning.
+ */
+@Configuration
+public class WebConfig implements WebMvcConfigurer {
+
+    private final ProtocolVersionInterceptor protocolVersionInterceptor;
+
+    public WebConfig(ProtocolVersionInterceptor protocolVersionInterceptor) {
+        this.protocolVersionInterceptor = protocolVersionInterceptor;
+    }
+
+    @Override
+    public void addInterceptors(InterceptorRegistry registry) {
+        registry.addInterceptor(protocolVersionInterceptor)
+                .addPathPatterns("/api/v1/data/**", "/api/v1/agents/**")
+                .excludePathPatterns(
+                        "/api/v1/health",
+                        "/api/v1/api-docs/**",
+                        "/api/v1/swagger-ui/**",
+                        "/api/v1/swagger-ui.html"
+                );
+    }
+}

cameleer3-server-app/src/main/java/com/cameleer3/server/app/interceptor/ProtocolVersionInterceptor.java

@@ -0,0 +1,46 @@
+package com.cameleer3.server.app.interceptor;
+
+import com.fasterxml.jackson.databind.ObjectMapper;
+import jakarta.servlet.http.HttpServletRequest;
+import jakarta.servlet.http.HttpServletResponse;
+import org.springframework.http.MediaType;
+import org.springframework.stereotype.Component;
+import org.springframework.web.servlet.HandlerInterceptor;
+
+import java.util.Map;
+
+/**
+ * Validates that all requests to data and agent endpoints include the
+ * {@code X-Cameleer-Protocol-Version} header with value {@code "1"}.
+ * <p>
+ * Requests missing the header or using an unsupported version receive a 400 response
+ * with a JSON error body.
+ */
+@Component
+public class ProtocolVersionInterceptor implements HandlerInterceptor {
+
+    private static final String HEADER_NAME = "X-Cameleer-Protocol-Version";
+    private static final String SUPPORTED_VERSION = "1";
+
+    private final ObjectMapper objectMapper;
+
+    public ProtocolVersionInterceptor(ObjectMapper objectMapper) {
+        this.objectMapper = objectMapper;
+    }
+
+    @Override
+    public boolean preHandle(HttpServletRequest request, HttpServletResponse response,
+                             Object handler) throws Exception {
+        String version = request.getHeader(HEADER_NAME);
+
+        if (version == null || !SUPPORTED_VERSION.equals(version)) {
+            response.setStatus(HttpServletResponse.SC_BAD_REQUEST);
+            response.setContentType(MediaType.APPLICATION_JSON_VALUE);
+            objectMapper.writeValue(response.getWriter(),
+                    Map.of("error", "Missing or unsupported X-Cameleer-Protocol-Version header"));
+            return false;
+        }
+
+        return true;
+    }
+}